/*
 * Copyright 2000-2016 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.intellij.util.containers;

import org.jetbrains.annotations.NotNull;

import java.util.Collection;
import java.util.Enumeration;
import java.util.concurrent.ConcurrentMap;

/**
 * Base interface for concurrent (long key -> V value) map
 * Null values are NOT allowed
 * <p>
 * Methods are adapted from {@link java.util.concurrent.ConcurrentMap} to long keys
 *
 * @see java.util.concurrent.ConcurrentMap
 */
public interface ConcurrentLongObjectMap<V> {
    /**
     * @return written value
     */
    @NotNull
    V cacheOrGet(long key, @NotNull V value);

    boolean remove(long key, @NotNull V value);

    /**
     * @param key      key with which the specified value is associated
     * @param oldValue value expected to be associated with the specified key
     * @param newValue value to be associated with the specified key
     * @return {@code true} if the value was replaced
     * @see ConcurrentMap#replace(java.lang.Object, java.lang.Object, java.lang.Object)
     */
    boolean replace(long key, @NotNull V oldValue, @NotNull V newValue);

    /**
     * @param key   key with which the specified value is associated
     * @param value value to be associated with the specified key
     * @return the previous value associated with the specified key, or
     * {@code null} if there was no mapping for the key.
     * (A {@code null} return can also indicate that the map
     * previously associated {@code null} with the key,
     * if the implementation supports null values.)
     * @see ConcurrentMap#replace(java.lang.Object, java.lang.Object)
     */
    V replace(long key, @NotNull V value);

    // regular Map methods
    V put(long key, @NotNull V value);

    V get(long key);

    V remove(long key);

    boolean containsKey(long key);

    void clear();

    @NotNull
    Iterable<LongEntry<V>> entries();

    @NotNull
    long[] keys();

    /**
     * @return Approximate number of elements in the map.
     * The usage is discouraged since
     * First, in concurrent context it doesn't have much sense
     * and Second, for weak- or soft- keyed maps it returns the total number of references
     * rather than alive values because otherwise it would be too expensive
     */
    int size();

    boolean isEmpty();

    @NotNull
    public Enumeration<V> elements();

    @NotNull
    Collection<V> values();

    boolean containsValue(@NotNull V value);

    /**
     * @return the previous value associated with the specified key,
     * or {@code null} if there was no mapping for the key
     */
    V putIfAbsent(long key, @NotNull V value);

    interface LongEntry<V> {
        long getKey();

        @NotNull
        V getValue();
    }
}
